html {
  position: relative;
  min-height: 100%;
}
@-ms-viewport       { width: device-width; }
body {
    font-family: "Helvetica Neue", Helvetica, STheiti, "Microsoft YaHei", "微软雅黑", FangSong, "仿宋", Arial, Tahoma, sans-serif, serif;
    
}
.footer {
    position: absolute;
    bottom: 0;
    width: 100%;
    /* Set the fixed height of the footer here */
    height: 40px;
    background-color: #f5f5f5;
    border-radius: 0 0 20px 20px;
}
.header {
    position: absolute;
    top: 0;
    width: 100%;
    /* Set the fixed height of the footer here */
    height: 25px;
    background-color: #f5f5f5;
}
.sidebar {
  display: none;
}
@media (min-width: 768px) {
  .sidebar {
    position: fixed;
    top: 25px;
    bottom: 0;
    left: 0;
    z-index: 1000;
    display: block;
    padding: 20px;
    overflow-x: hidden;
    overflow-y: auto; /* Scrollable contents if viewport is shorter than content. */
    background-color: #f5f5f5;
    border-right: 1px solid #eee;
  }
}